US plans Zika study of Olympic team

The US National Institutes of Health will fund a study to monitor US athletes, coaches and members of the Olympic Committee staff for exposure to Zika virus while in Brazil, with the hope of gaining better understanding of how it persists in the body and the potential risks it poses.

The study, announced on Tuesday, will investigate the incidence of Zika virus infection, identify potential risk factors for infection, evaluate how long the virus remains in bodily fluids, and study the reproductive outcomes of Zika-infected participants for up to one year.

Brazil, which has been hardest hit by the mosquito-borne virus spreading across the Americas, hosts the Summer Olympics in Rio de Janeiro next month.

The virus can cause potentially severe birth defects in babies whose mothers were infected during pregnancy, including microcephaly - a birth defect marked by small head size that can lead to developmental problems.

It has also been linked to Guillain-Barre, a rare neurological syndrome that can cause temporary paralysis in adults.

The connection between Zika and microcephaly first came to light last autumn in Brazil, which has now confirmed more than 1600 cases of microcephaly that it considers to be related to Zika infections in the mothers.

Zika is the first known mosquito-borne virus that can also be transmitted via unprotected sex with an infected male partner, leading to imprecise recommendations of how long couples should abstain or refrain from unprotected sex if the woman is pregnant or hoping to become pregnant.

Study participants will provide samples of bodily fluids to be tested for Zika and related viruses, such as dengue, which will help identify people who are infected but asymptomatic.

As many as 80 per cent of those who contract Zika do not display the classic symptoms, such as fever, rash and red eyes, researchers have said.